Field of the Invention
The present invention relates to a light source unit including an area of a luminescent material that emits luminescent light in the green wavelength range on part of a member that is situated on an optical path of light in the blue wavelength range, and a projector.
Description of the Related Art
Japanese Unexamined Patent Publication No. 2011-175000 (JP-2011-175000 A) discloses a projector utilizing a field sequential system (a time-division system) in which beams of light of a plurality colors (red, green, blue, white) are shone on to a display element repeatedly and the beams of light of the plurality of colors that are modulated by the display element are then combined on a time basis to thereby generate a colored image.
Japanese Unexamined Patent Publication No. 2002-90883 (JP-2002-90883 A) discloses a projector in which light emitted by a high pressure mercury-vapor lamp is shone on to a wavelength conversion optical element where the light is turned reddish or greenish and the light whose color is corrected in this way by the wavelength conversion optical element is shone on to a light valve, so that light that has passed through the light valve is projected.
Incidentally, it happens occasionally that blue light from a blue light source does not form ideal blue light. Namely, the blue light from the blue light source contains light of a short wavelength, in which case the blue light looks purplish blue. In the event that the blue light source is used for the blue light source described in Patent Document 1 (JP-2011-175000 A), the color balance will be lost.
Then, a problem that the invention is to solve is that even though blue light that is emitted from a blue light source looks purplish blue, the blue light can be corrected to be close to the ideal blue.
With a view to solving the problems, the invention provides a light source unit including a blue light source that emits blue light, an optical plate that intersects an axis of the blue light emitted by the blue light source and on which a luminescent area and a light transmission area are provided along a circumferential direction that passes through a point of intersection with the axis of the blue light, a rotational driving device that rotates the optical plate in the circumferential direction, and a wavelength range adding filter that is provided on an optical path of the blue light that is emitted from the blue light source and that passes through the light transmission area for adding light in a wavelength range of which wavelengths are longer than the wavelength of the blue light to the blue light.
According to the invention, even though the blue light that is emitted by the blue light source looks purplish blue, since the light in the wavelength range of which the wavelengths are longer than the wavelength of the blue light is combined with the blue light, the light that passes through the wavelength range adding filter is corrected to be close to the ideal blue.